Trigger an event of a different object on object collision BGE
While you can simply plug a senor from one object into an actuator on another, I find it cleaner to use messages.

Have object one (the ghost) trigger a message. Then on object two (the coin) have a message sensor trigger the motion.

Her are the logic bricks for the sensor object. It is just a collision sensor and a message actuator.


Then on the coin object add a message sensor, to trigger whatever you need.


Note the subject in both message logic bricks has to be the same.



Now if you just want to go the quick and easy way (yet very messy) then just select both the sensor object and the coin and hook up the logic bricks cross object in the logic editor.